YASKAWA VIPA System MICRO M13-CCF0000 - Page 166

If the slave announces an error, the function code is send back with an "ORed" 80h.
Without an error
, the function code is sent back.
Slave answer: Function code OR 80h ® Error
Function code ® OK
1 word
High-byte Low-byte
The shown check sums CRC at RTU and LRC at ASCII mode are automatically added to
every telegram. They are not shown in the data block.
Code 01h: Read n bits of master output area 0x
Code 02h: Read n bits of master input area 1x
Command telegram
Slave address Function code Address 1. bit Number of bits Check sum
CRC/LRC
1byte 1byte 1word 1word 1word
Respond telegram
Slave address Function code Number of
read bytes
Data 1. byte Data 2. byte ... Check sum
CRC/LRC
1byte 1byte 1byte 1byte 1byte 1word
max. 250byte
03h: Read n words of master output area 4x
04h: Read n words master input area 3x
Respond of the slave
Byte sequence in a word
Check sum CRC, RTU,
LRC
Read n bits 01h, 02h
Read n words 03h, 04h
VIPA System MICRO
Option: PtP communication
Modbus - Function codes
HB400 | CPU | M13-CCF0000 | en | 16-47 166